There exists a desire for cosmetic preparations available in numerous variants in order to adapt to different situations and different user characteristics (e.g., skin type). Thus, users may like to have lipsticks with various retention powers. In general, a person uses the same lipstick all day. However, present lipsticks are not adapted to the time of day, which may be desirable because if the lipstick is applied early in the morning it is desirable to have maximum retention power, whereas limited retention power for lipstick applied late in the evening may be desirable.
Lipsticks exist having different retention powers, because they contain varying quantities of a retention active agent. However, a user may not always think to adapt the lipstick to circumstances and does not find it practical to maintain several different lipsticks during the day.
The problems are of interest because the required retention power is not merely inversely proportional to time of day. With lipstick, the user may expect lipstick applied immediately before a meal to present good retention power so as to avoid leaving marks on glasses, for example.
With a hair spray, the user may desire its retention power to be at its greatest if the preparation is applied in the morning, and for its retention power to be limited if it is applied in the evening. In general, a person may comb out the hair in the evening. Thus, it is desirable for retention power to be limited in the evening to avoid inconvenience. The user may prefer preparations with greater wetting power to achieve good retention power in the morning, and preparations that are drier in the evening because they present lower retention powers.
Situations may be complicated because a person may use a hair spray in the morning, but requires a formula with little wetting power because wetter formulas take longer to dry, sometimes as much as 15 minutes, before it is possible to be active.
The user may be faced with a problem of choice when deciding what product to acquire. This can lead to hesitation in selecting one strength rather than another, because the user knows in advance that the choice is not easy. A user may acquire several strengths, but that solution may not be practical, for at least the reasons of storage space and expense.
Furthermore, even though manufacturers may attempt to clearly identify the strengths of their products and to display the corresponding information on the packaging, a user can make a mistake at the time of application. If manufacturers add other signs so that users can recognize strengths, those additional signs run the risk of being difficult to recognize or remember for some users.
The desire to have different strengths is not limited to those described above, but may also apply to preparations for providing protection against the sun, drying, high or low temperatures, antiperspirants and deodorants, fragrances, and hair gels.
It is possible to make products in a variety of strengths or to make a product in a single strength and rely on the user for managing application thereof so as to adjust its strength.
For example, it is possible to make antiperspirants in a variety of strengths. However, manufacturers have not typically opted for this approach for at least the reason that surveys have shown that users may not like the clutter of several products. The user may adjust the strength of a product by varying the quantity applied. However that can lead to problems, because it may be difficult to apply small quantities. It may be quite easy to apply large quantities, but the user can then be troubled by the problems of discomfort that can lead to, for example concerning the sensation and appearance of wetness that remain for many minutes after application.
Furthermore, certain products cannot be made available in a variety of strengths. This may apply typically to products that are already made available in multiple colors, such as hair coloring products, for example.
Making such hair coloring products available in a variety of strengths may lead to a substantial increase the number of products available. However, under such circumstances, the user may not have an option other than to adapt a product as a function of the moment it is used, and this often leads to a result that may not be desirable.
Application FR 2 807 346 describes a flask including an electronic circuit enabling a message to be delivered when the user presses on a dispenser button. The flask may include at least one sensor of an external physical parameter, in particular a sensor of ambient lighting and/or ambient temperature.
The electronic circuit may include a microcontroller that receives data from a clock. The message that is delivered may take account of the time of day or of the time that has elapsed since the previous use.